Blank and paper container

Abstract

The blank sheet provided for paper containers can suppress blank warping, thereby reducing the possibility of blockage between various rollers in the manufacturing line. An insulating sleeve (2) as a blank sheet, the blank sheet being used as an insulating sheet for paper cups (1) of paper containers, is characterized by having a coating layer (3), which is formed by applying an aqueous coating agent to at least one of the front or back sides of the sheet body (2A) of the insulating sleeve (2) and drying the aqueous coating agent, the coating layer (3) on the front or back sides of the sheet body (2A) being formed at multiple locations with uncoated surfaces (4) spaced apart.

Description

Technical Field

[0001] This invention relates to blanks for paper containers and paper containers having the blanks. Background Technology

[0002] In the past, most paper containers, such as paper cups, were made using paper blanks as the main material.

[0003] For example, Patent Document 1 discloses a paper cup as a paper container in which an insulating sleeve made of blank sheet is wound around the outer periphery of the main body of the paper container.

[0004] In such paper containers, for purposes such as heat-sealing bonding, lamination is often performed to cover either the front or back of the blank used for the paper container with a film such as resin.

[0005] However, when lamination is performed to cover either the front or back of the blank with a film made of resin or the like, the film shrinks when the blank changes from a heated state to a room temperature state, and the blank warps toward the side covered by the film.

[0006] On the other hand, the blanks used for paper containers are passed between various rollers on the manufacturing line during mass production.

[0007] At this point, the following problem was discovered independently: when the warping of the blank is large, the possibility of blockages and other malfunctions during blank handling on the manufacturing line increases.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2016-000623 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] Therefore, the present invention was made in view of the above-mentioned problems, and its object is to provide a blank for paper containers and a paper container having the blank: which can suppress blank warping and thereby reduce the possibility of blockage between various rollers in the manufacturing line during mass production.

[0013] Methods for solving problems

[0014] In order to solve the above-mentioned problems, the inventors have invented a preform for use in paper containers, wherein the preform has a coating layer formed by applying an aqueous coating agent to at least one of the front or back sides of the preform body and drying the aqueous coating agent, and the coating layer on the front or back sides of the preform body is formed at multiple locations at intervals.

[0015] The preform of the first invention is used for paper containers, characterized in that the preform has a coating layer formed by applying an aqueous coating agent to at least one of the front or back sides of the preform body and drying the aqueous coating agent, wherein the coating layer on the front or back sides of the preform body is formed at multiple locations spaced apart.

[0016] The blank of the second invention is characterized in that the coating layer at multiple locations is formed symmetrically on the front or back of the blank body.

[0017] The blank of the third invention is characterized in that, in the first or second invention, the coating layer is present only on one of the front or back sides of the blank body.

[0018] The blank of the fourth invention is characterized in that the thickness of the coating layer is 5 μm to 20 μm in any of the first to third inventions.

[0019] The blank of the fifth invention is characterized in that the ratio of the coating area occupied by the coating layer on the front or back side of the blank body is less than 80%.

[0020] The blank of the sixth invention is characterized in that the ratio of the coating area occupied by the coating layer on the front or back side of the blank body is 17% or more.

[0021] The preform of the seventh invention, in any of the first to sixth inventions, is characterized in that the difference in absorbance between the front and back sides of the sheet body on which the coating layer is formed in multiple locations is 15.5 g / m². 2 the following.

[0022] The blank of the eighth invention is characterized in that, in any of the first to seventh inventions, the blank is an insulating sheet covering the outer side of the paper container body of the paper container.

[0023] The blank of the 9th invention is characterized in that the paper container body is a paper cup body, and the heat insulation sheet is a heat insulation sleeve wound around the outer periphery of the main body portion of the paper cup body.

[0024] The paper container of the 10th invention is characterized in that the paper container body directly or indirectly has a blank of any one of the inventions from the 1st to the 9th invention.

[0025] The paper cup of the 11th invention is characterized in that the paper cup has a blank of the 9th invention as the insulating sleeve wound around the outer periphery of the main body portion of the paper cup body.

[0026] Invention Effects

[0027] According to the present invention with the above-described structure, a coating layer formed by applying an aqueous coating agent to at least one of the front or back sides of the preform body used for paper containers and drying the aqueous coating agent is formed at multiple locations with spacing. Experimental results show that preform warping can be suppressed. Therefore, the possibility of clogging between various rollers on the manufacturing line during mass production can be reduced. Attached Figure Description

[0028] Figure 1 (a) is a partially sectional side view showing a paper cup, a paper container according to an embodiment of the present invention. Figure 1 (b) is shown as Figure 1 (a) Top view of the back of the insulating sleeve of the paper cup, i.e. the blank sheet.

[0029] Figure 2 This is a magnified view of a portion. Figure 1 (b) is a partial enlarged view of the back of the insulating sleeve of the paper cup, which is used as the insulating sheet for the paper cup.

[0030] Figure 3 This is a table showing the results of Experiment 1.

[0031] Figure 4 This is a table showing the results of Experiment 2.

[0032] Figure 5 This is a table showing the results of Experiment 3.

[0033] Figure 6 This is a table showing the results of Experiment 4. Detailed Implementation

[0034] Hereinafter, embodiments illustrating the application of the present invention will be described with reference to the accompanying drawings.

[0035] [Implementation Method]

[0036] First, use Figure 1 and Figure 2 The paper cup 1, which is an embodiment of the present invention, will be described. Figure 1 (a) is a partially sectional side view showing the paper cup 1, which is a paper container according to an embodiment of the present invention. Figure 1 (b) is shown as Figure 1 (a) Top view of the back of the insulating sleeve 2 of the paper cup 1, i.e. the blank sheet. Figure 2 This is a magnified view of a portion. Figure 1(b) is a partial enlarged view of the back side of the insulating sleeve 2, which serves as the insulating sheet for the paper cup 1.

[0037] like Figure 1 As shown in (a), the paper cup 1, which is an embodiment of the present invention, has: a paper cup body 11 as the main body of the paper container; and an insulating sleeve 2 as a blank, which is an insulating sheet wound around the outer periphery of the main body portion 11a of the paper cup body 11.

[0038] The paper cup body 11 is composed of a bottomed cylindrical body part 11a having a curled part 11b at the upper edge.

[0039] like Figure 1 As shown in (b), the insulation sleeve 2 has: a sheet body 2A, which is mainly made of paper; and a coating layer 3, which is formed by coating the back of the sheet body 2A with an aqueous coating and drying the aqueous coating.

[0040] The main body 2A is fan-shaped and covers the outer side of the main body 11a when it is rolled around the outer periphery of the main body 11a of the paper cup body 11.

[0041] The coating layer 3 is formed on multiple parts of the back of the sheet body 2A by providing uncoated surfaces 4 as intervals.

[0042] The coating layers 3 on these multiple locations are of approximately the same area, and the uncoated surfaces 4, which serve as intervals, are also approximately the same. Furthermore, the coating layers 3 on these multiple locations are symmetrical about the back side of the sheet body 2A.

[0043] Furthermore, the coating layer 3 in these multiple locations is not limited to... Figure 1 The vertical stripes shown in (b) can also be implemented in other pattern shapes such as horizontal stripes or grids.

[0044] Moreover, such as Figure 2 As shown, the coating layer 3 at these multiple locations has multiple cracks 5.

[0045] Alternatively, the coating layer 3 at these multiple locations can also be implemented without multiple cracks 5.

[0046] Furthermore, the heat insulation sleeve 2 is wound around the outer periphery of the main body 11a of the paper cup body 11, and is bonded and installed by heating the coating layer 3 as a heat seal.

[0047] Regarding the thickness of the coating layer 3 at the multiple locations, considering the heat-sealing bonding purpose based on the coating layer 3 at the multiple locations, a minimum thickness of 5 μm is required, and a thickness exceeding 20 μm would be wasteful. Therefore, it is known that 5 μm to 20 μm is preferred, but other ranges are also possible.

[0048] Furthermore, as shown in the results of Experiment 1 described later, the ratio of the coating area occupied by the coating layer 3 on the back side of the sheet body 2A is preferably 80% or less, more preferably 60% or less.

[0049] Furthermore, as shown in the results of Experiment 2 described later, the ratio of the coating area occupied by the coating layer 3 on the back side of the sheet body 2A is preferably 17% or more.

[0050] Furthermore, as shown in the results of Experiment 3 described later, the difference in absorbency between the front and back sides of the sheet body 2A, to which the coating layer 3 is formed in multiple locations, is preferably 15.5 g / m². 2 the following.

[0051] Furthermore, as shown in the results of Experiment 4 described later, when the coating layer 3 has multiple cracks 5 in multiple locations, the area ratio of the multiple cracks 5 in the coating layer 3 is preferably 11.8% or less per unit area (here, the aforementioned unit area is 1 mm). 2 ).

[0052] In addition, for the purpose of further improving heat insulation, having a high-end feel due to a good appearance, and increasing the value of the product, a coating layer 3 can also be applied to the front side of the main body 2A.

[0053] Furthermore, the resins used as the main components of the aqueous coatings used to form the coating layer 3 include, for example, polyolefin resins, polypropylene resins, polyethylene resins, modified polypropylene resins, modified polyethylene resins, polyethyleneimine resins, ethylene vinyl acetate copolymer resins, polyolefin ionomer resins, ethylene acrylic acid copolymer resins, ethylene methacrylate copolymer resins, ethylene methyl methacrylate copolymer resins, ethylene vinyl chloride copolymer resins, ethylene methyl acrylate copolymer resins, polyvinyl alcohol resins, acrylic resins, acrylic acid copolymer resins, styrene acrylic acid copolymer resins, methacrylic acid resins, polymethyl methacrylate resins, methacrylic acid copolymer resins, vinyl chloride resins, polyvinylidene chloride resins, vinyl acetate resins, polyurethane resins, polyester resins, polyethylene terephthalate resins, polylactic acid resins, polyhydroxyalkanoic acid resins, polybutylene succinate resins, polyamide resins, copolynylon resins, polystyrene resins, styrene-maleic acid copolymer resins, phenolic resins, rosin-modified phenolic resins, etc.

[0054] In addition, for example, considering the environment, biodegradable resins or the like can be used as the main component of the water-based coating used to form the coating layer 3.

[0055] According to the embodiments of the present invention described above, a coating layer 3, formed by drying an aqueous coating applied to the back side of the sheet body 2A of the insulating sleeve 2 (which serves as a blank), is formed at multiple locations on the back side of the sheet body 2A with uncoated surfaces 4 spaced apart. This blank is an insulating sheet used as a paper cup 1 for paper containers. Experimental results, described later, show that warping of the insulating sleeve 2 (which serves as a blank) can be suppressed. This reduces the possibility of defects such as blank blockage on the manufacturing line during mass production.

[0056] Furthermore, in embodiments of the present invention, the coating layer 3 is used for heat-sealing bonding, which is superior to cold-glue bonding. Therefore, in embodiments of the present invention, in addition to mass production of paper cups 1, there are advantages such as increased throughput and reduced defect rate.

[0057] Furthermore, in embodiments of the present invention, the coating layers 3 at multiple locations have approximately the same area, and the uncoated surfaces 4, which serve as intervals, are approximately the same. Moreover, the coating layers 3 at these multiple locations are symmetrical about the back side of the sheet body 2A. Therefore, in embodiments of the present invention, uniformity of the adhesive strength between the heat insulation sleeve 2 and the outer periphery of the main body portion 11a of the paper cup body 11 can be ensured.

[0058] Furthermore, in embodiments of the present invention, the coating layer 3 at multiple locations has multiple cracks 5. Therefore, in embodiments of the present invention, for example, the coating layer 3 can be formed by repeatedly applying the next coating layer before the previous coating layer dries, thus enabling the coating layer 3 to be formed in a short time and achieving high manufacturing efficiency.

[0059] [Example 1]

[0060] The results of Experiment 1, conducted to confirm the effectiveness of the present invention, will be described below.

[0061] In this experimental verification 1, samples from Comparative Example 1, Invention Example 1, Invention Example 2, and Invention Example 3 all used samples with a thickness of 0.239 mm and a basis weight of 200 g / m³. 2 A fan-shaped blank.

[0062] In the sample of Comparative Example 1, the coating area of ​​the 10 μm thick coating layer 3 on one side of the blank is 100%.

[0063] In the sample of Example 1 of the present invention, the coating layer 3 with a thickness of 10 μm occupies 80% of the coating area on one side of the blank.

[0064] In the sample of Example 2 of the present invention, the coating layer 3 with a thickness of 10 μm occupies 60% of the coating area on one side of the blank.

[0065] In the sample of Example 3 of the present invention, the coating area occupied by the coating layer 3 with a thickness of 10 μm on one side of the blank is 40%.

[0066] The presence or absence of warping in the samples of Comparative Example 1, Example 1 of the present invention, Example 2 of the present invention, and Example 3 of the present invention, as configured in this way, was confirmed, and the results were obtained. Figure 3 The test results are shown.

[0067] Furthermore, the aqueous coating used to form the coating layer 3 of the samples of Comparative Example 1, Example 1 of the present invention, Example 2 of the present invention, and Example 3 of the present invention was an aqueous coating containing 5% diluent (isopropanol) added to a water-based coating manufactured by Mitsui Chemicals Co., Ltd., which uses an ionomer (ethylene methacrylate copolymer) as the main component and has a solids concentration of 35%. Then, coating was performed such that the coating area of ​​one side of each sample reached the target ratio, and the coating was dried in an oven at 140°C for 50 seconds.

[0068] like Figure 3 As shown, the sample of Comparative Example 1 has warping on the coating layer 3 side (warping height is 20 mm). In contrast, the samples of Example 1, Example 2, and Example 3 of the present invention do not have warping.

[0069] Therefore, it is confirmed that the ratio of the coating area occupied by the coating layer 3 on the front or back of the sheet body 2A is preferably 80% or less.

[0070] [Example 2]

[0071] The results of Experiment 2, conducted to confirm the effectiveness of the present invention, will be described below.

[0072] In this experimental verification 2, samples of Comparative Example 2 and Invention Example 4 were prepared using the same method as in Experimental Verification 1 above.

[0073] In the sample of Comparative Example 2, the coating layer 3 with a thickness of 10 μm occupies 10.7% of the coating area on one side of the blank.

[0074] In the sample of Example 4 of the present invention, the coating area occupied by the coating layer 3 with a thickness of 10 μm on one side of the blank is 16.8%.

[0075] The samples of Comparative Example 2 and Example 4 of the present invention, constructed in this way, were subjected to a peel test from the bonded body. Those exhibiting the required adhesive strength were deemed good, while those lacking the required adhesive strength were deemed poor. After confirmation, the following results were obtained. Figure 4 The test results are shown.

[0076] like Figure 4 As shown, the sample in Comparative Example 2 was defective. In contrast, the sample in Example 4 of the present invention was good.

[0077] Therefore, it is confirmed that, on the front or back of the sheet body 2A, especially in cases where adhesion is the purpose, the ratio of the coating area occupied by the coating layer 3 is preferably 17% or more.

[0078] [Example 3]

[0079] The results of experiment 3, conducted to confirm the effectiveness of the present invention, will be described below.

[0080] In this experimental verification 3, in addition to the samples of Comparative Example 1 and Example 1 of the present invention used in Experimental Verification 1, the sample of Example 5 of the present invention, in which the coating layer 3 with a thickness of 10 μm on one side of the blank occupies 30% of the coating area, was also used.

[0081] Then, the absorbency of the front and back sides of the sheet body 2A of each sample was measured, and the difference in absorbency of each sample was calculated.

[0082] In addition, the absorbency of this Cobb was measured over a period of 2 minutes and over a measurement area of ​​20 cm². 2 It was carried out under the conditions of (JIS P8140).

[0083] like Figure 5 As shown, it was confirmed that in the sample of Comparative Example 1, the difference in absorbency between the front and back sides of the tablet body 2A was 17.5 g / m². 2 In contrast, in the samples of Example 1 and Example 5 of this invention, the difference in absorbency between the front and back sides of the sheet body 2A was 15.5 g / m². 2 the following.

[0084] This confirms that when the coating area of ​​the coating layer 3 on the front or back of the sheet body 2A is less than 80%, the moisture absorption difference between the front and back of the sheet body 2A decreases, and warping can be suppressed by the decrease in moisture absorption difference between the front and back of the sheet body 2A.

[0085] [Example 4]

[0086] The results of experiment 4, conducted to confirm the effectiveness of the present invention, will be described below.

[0087] In this experimental verification 4, samples of Comparative Example 3 and Example 6 of the present invention were prepared by using a method that was roughly the same as that of Experimental Verification 1 above. The ratio of the coating area occupied by the coating layer 3 with a thickness of 10 μm on one side of the blank was 80%. However, unlike the sample of Example 1 of the present invention, the coating layer 3 had multiple cracks 5.

[0088] In the sample of Comparative Example 3, the area ratio of multiple cracks 5 in the coating layer 3 was 11.84% per unit area (here, the aforementioned unit area is 1 mm). 2 ).

[0089] In the sample of Example 6 of the present invention, the area ratio of the plurality of cracks 5 in the coating layer 3 is 11.8% per unit area (here, the aforementioned unit area is 1 mm). 2 ).

[0090] Five samples of Comparative Example 3 and Example 6 of the present invention with such configurations were prepared respectively to confirm whether there was any case of surface lifting of the coating layer 3.

[0091] exist Figure 6 The test results are shown in Comparative Example 3. In 2 out of 5 samples, the surface of the coating layer 3 of the sample floated.

[0092] In contrast, in the samples of Example 6 of the present invention, the surface of the coating layer 3 of none of the five samples was raised.

[0093] The test results confirm that when the area ratio of multiple cracks 5 in the coating layer 3 exceeds 11.8% per unit area (here, the aforementioned unit area is 1 mm), the situation is as follows: 2 When the coating layer 3 has multiple cracks 5 in multiple locations, the surface of the coating layer 3 will lift, resulting in slightly lower quality. Therefore, although manufacturing efficiency is high when the coating layer 3 has multiple cracks 5 in multiple locations, it is preferable that the area ratio of multiple cracks 5 in the coating layer 3 is less than 11.8% per unit area (here, the aforementioned unit area is 1 mm). 2 ).

[0094] Furthermore, based on the results of experiments 1 to 4 conducted to confirm the effectiveness of the present invention, it can be concluded that the present invention is particularly effective when implemented in a manner in which the coating layer 3 is only applied to one side of the sheet body 2A.

[0095] The embodiments of the present invention have been described above, but these embodiments are provided as examples and are not intended to limit the scope of the invention. This new embodiment can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, and are included within the scope of the invention as described in the claims and their equivalents.

[0096] In the above embodiments, the present invention is applied only to paper cup 1, but is not limited thereto. For example, it can also be applied to other paper containers such as paper containers for food and medicine.

[0097] Label Explanation

[0098] 1: Paper cup (paper container); 11: Paper cup body (paper container body); 11a: Main body; 11b: Curled part; 2: Insulation sleeve (blank sheet); 2A: Sheet body; 3: Coating layer; 4: Uncoated surface (spacer); 5: Crack.

Claims

1. A blank sheet for use in paper containers, characterized in that, The blank has a coating layer formed by applying an aqueous coating agent to at least one of the front or back sides of the blank body and allowing the aqueous coating agent to dry. The coating layer on the front or back of the sheet body is formed at intervals in multiple locations. The ratio of the coating area on the front or back of the main body of the sheet to the coating area is more than 40% and less than 80%. The coating layer at the multiple locations has multiple cracks, and the area occupied by these multiple cracks is less than 11.8% per unit area.

2. The blank according to claim 1, characterized in that, The coating layers at multiple locations are formed symmetrically on the front or back of the sheet body.

3. The blank according to claim 1 or 2, characterized in that, The coating layer is present only on one of the front or back sides of the sheet body.

4. The blank according to claim 1 or 2, characterized in that, The thickness of the coating layer is 5μm to 20μm.

5. The blank according to claim 1 or 2, characterized in that, The difference in water absorption between the front and back surfaces of the sheet body on which the coating layer having a plurality of sites is formed is 15.5 g / m 2 The following.

6. The blank according to claim 1 or 2, characterized in that, The blank sheet is an insulating sheet that covers the outer side of the paper container body of the paper container.

7. The blank according to claim 6, characterized in that, The paper container body is a paper cup body, and the heat insulation sheet is a heat insulation sleeve wound around the outer periphery of the main body of the paper cup body.

8. A paper container, characterized in that, The paper container body has, directly or indirectly, the blank as described in any one of claims 1 to 7.

9. A paper cup, characterized in that, The paper cup has the blank of claim 7 as the insulating sleeve wound around the outer periphery of the main body portion of the paper cup body.

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